1. Field of the Invention
The present invention relates to a conveying installation with a linear motor drive which includes a stator placed along a travel path and at least one conveyor unit with at least one permanent magnet, wherein the conveyor unit is guided along the stator in a constrained manner.
2. Description of the Prior Art
A conveying installation of this type can be operated above ground as well as below ground. As a rule, several conveyor units travel on the travel path. The movement of the conveyor units is controlled by a computer. The spacing between the conveyor units is predetermined by local conditions. The conveyor units may be guided in a sliding manner or on rollers. The guidance of the conveyor units may be effected on the stator or on a separate guide rail which may form the travel path.
The control of the speed of the conveyor units and the spacing between the conveyor units does not pose a problem as long as no failures, for example, power failure or computer failure, occur. However, particularly in the case of power failure or computer failure, difficulties may occur in the sequential movement of conveyor units which may have the result that the conveyor units run up against each other. The danger exists especially along outwardly or downwardly inclined travel paths in mining operations below ground.
In order to prevent this potential danger, it would be conceivable to install brakes in the conveyor units. However, it is difficult to install these brakes because the conveyor units themselves do not have their own energy supplies and, thus, after the conveyor units have been stopped, a further movement of the units is only possible after the brakes of the conveyor units have been manually or by means of an independent energy source been switched back from the braking position into the operating position.
It is, therefore, the primary object of the present invention to improve the conveying installation described above in such a way that a conveyor unit cannot be moved in an uncontrolled manner along the travel path even if unforeseeable problems occur, particularly with respect to the electrical energy supplied to the stator.